A/G polymorphism at position 49 in exon 1 of CTLA-4 gene in Chinese women with unexplained recurrent spontaneous abortion

To investigate whether A/G polymorphism at position 49 in exon 1 of cytotoxic T lymphocyte antigen-4 (CTLA-4) gene confers the susceptibility to unexplained recurrent spontaneous abortion in Chinese population. One hundred and sixty-eight restrictive Chinese women with unexplained recurrent spontaneous abortion (URSA) and 117 women with normal pregnancy as control were included in this study. Polymerase chain reaction restrictive fragment length polymorphism (PCR-RFLP) was used to detect the polymorphism at position 49 in exon 1 of CTLA-4 gene. The frequency of alleles G/A, genotypes AA/AG/GG and phenotypes A+ (AA + AG)/G+ (GG + AG) of CTLA-4 were compared between URSA patients and controls. The different distributions of alleles G/A, genotype AA/AG/GG and phenotypes A+/G+ of CTLA-4 were observed between URSA patients and controls. The frequencies of both G allele [68.4% (230/336) vs 59.4% (139/234), P < 0.05] and GG genotype [48.8% (82/168) vs 33.3% (39/117), P < 0.05] were significantly higher in URSA group